Partial oxidation of hydrocarbons



April 7,. 1936. J. H. JAMES PARTIAL OXIDATION OF HYDROCARBONS OriginalFiled Jafi. 6'. 1921 2 s -sh 1 INVENTOR J. H. JAMES PARTIAL OXIDATION OFHYDROCARBONS pril 7, 1936.

Original Filed Jan. 6. 1921 2 Sheets-Sheet 2 INVENTOR I I I l I I I I 1I l I n I Patented Apr. 7, 1936 PATENT OFFICE PARTIAL OXIDATION OFHYDROCABBONS Joseph Hidy James, Pittsburgh, Pa" aulgnor to C. P. Byrncs,trustee, Sewickley, Pa.

Original application January 6, 1921, Serial No. 435,355. Divided andthis application April 12,

1929, Serial No. 354,551

11 Claims. (Cl. 260-116) upon the method set forth in my pendingapplication Serial No. 272,567, filed January 22, 1919, and certainother pending applications. In a large amount of further work done onsuch 10 methods, I have discovered means and methods for controlling thetemperature of the reactions,

and for increasing the percentages of useful 1 products obtained andimproving their quality for certain uses. I have also discovered that Ican,

5 simultaneously therewith, produce material percentages of hydrocarbonproducts, such as motorspirit, of less molecular weight than thehydrocarbon treated, owing to thermal decomposition.

I have also found an improved way of handling hydrocarbons of highmolecular weight such as are contained in large amounts in the cheaperpetroleums; and which are dimcult to vaporize and even when subjected tomy main process give poorer products.- For example, taking a heavyfraction from Mexican or California petroleum, I subject this or stillheavier fractions, to the oldiashioned atmospheric pressure crackingdistillation in vertical stills, as in the former process used toincrease the amount of kerosene produced. By suitable regulation of thestep it is possible to convert 70 to 80% of a heavy hydrocarbon fractioninto a product having a specific gravity about the same as that ofPennsylvania gas oil. This contains a considerable percentage of olefinhydrocarbons, being made up partly of those already present and partlyfrom the cracking operation. It also may contain some acetylenehydrocarbons. This distillation may be completely carried out so thatall the material is cracked and distilled except a layer of cake whichremains and is dug out of the still.

This operation lowers the boiling point and permits of easier handlingin my main partial combustion process. If, for producing motor spirit,or special flotation oil, for example, by my process, a hydrocarbon ofstill lower molecular weight is desired, this cracked product may besubjected tovapor phase cracking, preferably at about 400 C. and in thepresence of a catalyst. Such catalyst may be any of those hereinaftermentioned, and in addition finely divided metals, such as nickel. Ineither case the product oxidizes more easily in my process of partialcombustion, and may in many cases be oxidized ata lower temperature,even as low as to C. I have also discovered that, by increasing thedepth or thickness of the catalytic layer in such processes, I canimprove both the quality and quantity of products obtained for certainpurposes; while at the same time increasing the amount of lower boilingpoint hydrocarbons produced. Under this phase or the invention, I mayincrease the total depth or thickness of the catalytic layer either byincreasing the thickness of a single layer of the material, or by usinga series of separated layers, or by both. I prefer to use a successionof separated layers, and in such case'I prefer to admit additional airto the hot mixed vapor material between each pair of catalytic layers;and to mix only a portion of the it) total amount of air required, withthe vapor passing to the first layer.

I also prefer to suck the vapor-air-mixture through the apparatus by asuction or exhaust device at the outlet end, located either between 13the catalyst and the condenser, or beyond the condenser and between thecondenser and the scrubbers, if the latter are used.

Where catalytic layers of relatively large area are employed under mymethod, I have found 0 that there is difficulty in controlling thetemperature in the reaction zone. The partial combustion reaction givesout heat, and with layers of large area the temperature tends to buildup and to rise with considerable rapidity as the 5 reactions proceed.With larger area layers, the heat generated will, of course, escape lesseasily than with those of smaller areas.

I have found several ways of overcoming this trouble with relativelylarge area layers. 30 First: 1 decrease the amount of air supplied forthe mixture and which Iwould otherwise supply to considerably above thattheoretically required to combine with and oxidize the vapor. I cut downthis air percentage to more nearly the theo- 35 retical amount, or tosuch theoretical amount, or even below it, as the temperature risesabove that desired, during the run.

Second: I supply a diluent, such as steam supplied as water fed into thevaporizer in regulated 40 amounts; or I may use fume gas fed into themixture.

Third: I employ several separated layers of catalytic material andsupply only a portion of the total air to the mixture passing to andthrough each screen. This is my preferred form.

Fourth: I may artificially cool the layer, particularly where only onelayer is used, by applying cooling fluid, directly or indirectly, to the50 outlet side of the layer.

Any one, or several, or all of these systems of controlling thetemperature may be used.

Reducing the air percentage or supplying steam or other diluent tends toretard the reactions in 5 the reaction one. Where the amount of air isreduced, or steam is supplied to hold down the temperature, the amountof partial combustion products will be somewhat reduced, where. a singlescreen is used; though this .system is entirely 60 i practicable withoutthe use of special cooling devices.

By using a series of separated catalytic layers with regulated airinlets between them, I can carry out the reactions in a stepby-stepmanner while more effectually controlling the temperature and keeping itwithin the desired limits at each layer. In this system the added airsupplied later will make up for the original deficit and for thedilution by nitrogen after the first reaction.

If a cooling system is used, cooling pipes with closed ends maybeapplied at the outlet side of the catalytic layerflthe blind endsbeing either in contact with the, layer, or embedded therein, or spacedat a slight distance therefrom. If the asbestos or other carrier coatedor impregnated with the catalytic material is packed between wire meshscreens, as I prefer, the wire screen may be cut away or punctured toreceive theclosed ends of the pipes; or these ends may simply contactwith the wire screen.. By controlling the flow of cooling fluid throughthis cooling system, I can aid in controlling the temperature andkeeping it within the desired limits. Water'or air cooling may be used,and the latter, if used, may pass through the cooler by natural orforced draft. In all cases this cooling should be on the outlet side, asthe hot vapor mixture must be kept in the vapor phase as it passes intoand through the reaction zone. Hence strong cooling of the vaporairmixture as it approaches the reaction zone would be objectionable.

In many cases, particularly where larger screens are used, my newdiscoveries will, especially for certain products, avoid the need ordesirability of re-vaporizing the condensed products and again treatingthem infaccordance with my partial combustion process; and at the sametime, the total value of the products is increased, both by theproduction of a light hydrocarbon and by the improved quantity andquality of the partial combustion products obtained, especially where agreater total thickness of layer or layers is used.

With a thicker single layer or a succession of separated layers, thealdehyde fatty acids produced are of better quality, being more freefrom substances which polymerize and impart objectionable odors andcolors to the products, such as soaps made therefrom, than with a thinscreen. Materials having objectionable odors may be largely removed byheating the product and blowing air through it for a few hours.

In the drawings, I

Figure 1 is a vertical section showing one form of apparatus forcarryingout my invention;

Figure 2 is a vertical section of a plural layer system; and

Figure 3 is a vertical section of apparatus having a single relativelythick catalytic layer.

Referring to the form of Figure 1, 2 represents the vaporizing and airmixing chamber, and 3, 3, suitable gas burners beneath the same. 4represents an oil inlet pipe from which the oil may drop upon a bafileplate, if desired. 6 is the air inlet pipe. I is a drain cock, and 8designates try-cocks. At the outlet end of the chamber, it isdecreased-in size somewhat, and in this portion are arranged twometallic screens 9, 9, consisting of thin metallic plates withperforations through them, the perforations in one plate preferablybeing staggered relatively to those in the next. These serve to morethoroughly mix the vapor and air, and also aid in preventing anyunvaporized oil from reaching the reaction zone. I0 is a catalytic layerwhich may contain a thermometer cured to each other and to the outletflange of the retort chamber. The casting II has closed end tubes II,with their open ends secured in its rear wall, and the casting I! hassmaller open end tubes II, with their rear ends secured in its rearwall. Water or air is circulated through this pipe system, the coolingfluid either entering the small tubes and passing back through the largetubes to a stack or outlet 5, or vice versa. The closed ends of thelarge tubes may contact with the outlet face of the catalytic layer orthe enclosing metal screen, or may be embedded in the layer, or may bespaced a slight distance apart from the layer and screen. In all casesthe intent is to abstract heat from the reaction zone to a regulableamount in order to control the temperature.

The bottom of the casting H is provided with an outlet channel l5, whichleads to an ordinary condenser I 6 having water inlet l1 and wateroutlet l8. The products condensing in the tubes of this condenser dropinto the condenser vessel I9, from which they may be tapped out througha pipe 20 into a product receiver 2|. leads from the closed vessel I9 toa vacuum pump, and an equalizing vacuum pipe 23 preferably connects thetwo vessels l 9 and 21, to provide freer discharge of the liquidproduct. 24 is a valved vent pipe, and 25 a valved tap for the receiver.

In the use of thisapparatus, the oil entering in a regulated feed isvaporized in the chamber 2 and mixed with a regulated amount of airentering through the pipe 6. The hot hydrocarbon vapor and air mixturepasses through the perforated plates 9, and thence through the catalyticlayer, where the partial combustion reactions take place. On leaving thelayer, the products strike the cooling system and pass down through thecondenser into the collector.

Steam may also be fed in in regulated amounts to the vaporizing chamber,although this is not necessary where thecooling system is properlyarranged and handled. A thin screen or a thicker screen may be used inthis apparatus, depending partly upon the kind of product desired. Ifthe heavier petroleum fractions are being used, steam will aid invaporization and also as a temperature equalizer. It also aids inkeeping the catalyst free from heavy organic materials, such as tars,which may tend to coat it and retard the passage of the mixture. Infact, although steam retards the action of the process, it is in somecases of industrial advantage, especially with a greater depth ofcatalyst; or with a series of catalytic layers, the continued action ofwhich will compensate for this retardation and complete the reactions toaldehyde fatty acids.

In carrying out these partial oxidation processes on this single screenform without lagging, the screens or catalytic layers sometimes becomeclogged, due to deposits which are apparently made up of carbon tars orsimilar material. This difliculty, if it occurs, can be overcome byblowing out or burning out the layer. In carrying this out I shut offthe oil feed and while keeping on the burners pass heated air throughthe screen for a sufficient time to clean it, or use steam in the sameway or both. By subjecting the screen to this action, at desiredintervals, it can be kept A pipe 22 ,ble in water.

in the desired porous and active condition. This clogging appears to belargely mechanical, and I have thus far found no chemical "sickeningaction on the catalytic material, which, when properly prepared, remainsactive indefinitely. Another way of cleaning the layer consists inswitching off the heavier oil feed and switching in a kerosene feed fora short interval of, say, one-half hour, at suitable periods, whendesired. This will serve to clear the catalytic layer probably bydissolving and releasing the gummy compounds. A wire screen may beembedded in the catalyst layer and thismay be connected to a source ofelectric current to heat the same to incandescence, when desired, inorder to start combustion of. the carbonaceous substances collecting inand clogging the catalytic material.

In this apparatus, the temperature of the reaction zone may becontrolled by regulating the vaporizing burners, by regulating theamount of air introduced, "by introducing regulated amounts of adiluent, such as steam or fume gas, and by passing cooling fluid throughthe cooling pipes at a regulated speed.

As illustrating the efiect of a cooling system, I will describe thefollowing example:

With a layer of catalytic material it" in diameter and thick and thecooling system having the closed pipeends set against the outer screenplate which holds the catalytic material in place, an experimentwas'made without any water circulating through the cooling system. Inthis case, the temperature of the catalyst rose too rapidly for goodpractice, the oil being fed. at 9.7 liters per hour and the air at about7 cu. ft. per minute. This test shows that the temperature rose sorapidly that with the particular hydrocarbon air ratio used, it wouldsoon reach a point where the reactions would pass into another andundesirable phase.

The cooling system above shown was then connected so that cold water wascirculated in through the smaller pipes and back through the other pipesand the water exit. Under these conditions, another experiment wascarried out. In this case, with oil fed at the rate of 9.7 liters perhour and air at the rate 01' 6- cu. ft. per minute, with suitableregulation of the heat under the vaporizer, the temperature was held atthe desired point of about 3'70 to 380 C. The oil treated was Waverlygas oil with a specific gravity of .032 and the water entered at atemperature of about 10 C. and was at a temperature of 27 C., as itemerged from the condenser. The total oil fed in this case was about37.5 liters and the product recovered amounted to 19 liters containingabout 45% of aldehyde fatty acid insolu- The reaction was kept undergood control and a good quality of products produced.

I will now describe a multiple screen form of my apparatus, one type ofwhich is shown in Figure 2. In this figure, 2 is the vaporizing and airmixing chamber, and 3 the burners underheath the same. 4* is the oiladmission pipe; b the air admission pipe; i the drain cock, and ittry-cocks. are separated metallic screens consisting of thin metallicplates with staggered perforations, these serving to give an excellentmixture and prevent liquid spray from reaching the reaction zone. Hi arethree catalytic layers spaced apart from each other. Each catalyst layeris preferably formed of asbestos carrying the catalyzing material, andis about one-half inch thick. This material is preferably packed betweenmetallic screens, there being about three a liter of water per hour.

screens on each side of the layer, the inner screen being of finer meshthan the outer ones, thus giving stifiness. Embedded in the catalystlayers are thermocouples 26, the wires of which lead to a commongalvanometer 21, from which the temperatures may be read. Anotherthermocouple 28 is placed in the vaporizer, and a switch 29 acts toconnect any of the thermocouples to the galvanometer to show thetemperature at any desired point. 3|] are valved supplemental air pipes,

leading into chambers 31 between the three catalyst layers to supply airto the mixture emerging from the catalyst zones. That is, after themixture with a partial amount of air admitted to it in the vaporizer haspassed through the first catalytic layer, a further amount of air ismixed with it, and the new mixture is passed through the secondcatalytic layer. Further air may then be added to the further oxidizedmixture, which is then passed through thethird catalytic layer.

I also preferably add a diluent to the mixture, this diluent beingeither steam, or fume gas taken from the exit of the apparatus. If steamis used, I preferably add it in the vaporizing chamber by feedingmeasured amounts of water into the oil pipe 4 The steam thus added actsboth as a diluent and also as an aid to vaporizing heavier distillates.In the form shown, I also employ fume gas for diluting the mixturesbetween the screens. Thus, the return pipe 32 leads a portion of thefume gas back from the vacuum or exhaust pump 33, through pipes 3t intothe valved air pipes 30. By this means, a carefully regulated. measuredamount of fume gas may be introduced as a diluent into ,the mixtures,between the catalytic layers.

I have shown the vaporizing chamber and the remainder of the apparatusthus described as lagged or covered with heat-insulating material 35,except where the burners act on the vaporizing chamber. This lagging isfound to be of advantage, as I have discovered that quick cooling of thevapor mixture tends to throw down tarry deposits, etc. From the outletchamber 35 of the apparatus, a long pipe 3? leads to the condenser lfi,thus giving gradual cooling in passing to the condenser. From thecondenser, the products drop into the vessel 119 from which they may betapped out through the pipe into the receptacle 2 Il pipe 22* connectedto the upper part of the vessel w and also the upper part of thecollecting vessel M through the pipe 23'. 3% is a valved pipe leadingfrom the exhaust pump to the scrubbers and the atmosphere.

Referring now to a run with an apparatus such as that shown in thisFigure 2:--the diameter of the catalytic screens was about 15 and oilwas fed at the rate of 6 liters per hour with of The oil used was arefining waste obtained at a plant running on Pennsylvania petroleum andshowing the following distillation: Up to 200- C None 200 to 250 C 11%250 to 300 C -s 51% 300 to 350 C 34% A residue above 350 C 4% Thespecific gravity of the oil at 15.6 C. was .819. The amount of olefinichydrocarbons as shown by the sulphuric acid test was 7.5%.

In a run of nearly four hours, the temperature in the vaporizer wasmaintained about 310=. The temperature of the first layer was about 330to 340. The temperature of the second layer was about 365 to 380. Thetemperature of the third layer was about 365 to 370. The volume of airat room temperature and pressure passing into the vaporizer was about2.5 to 3 cu. ft. per minute. The volume of air passing into the mixturebetween the first andsecond layers was about 1 to 1.5 cu. ft. perminute. The volume of air passing to the mixture between the second andthird layers was about 1 to 1.5 cu. ft. per minute.

In the latter part of the run, fume gas was fed into the mixture passingto No. 2 layer at the rate of about 2 cu. ft. per minute, no additionalfume gas being fed to the mixture passing to the third layer. A vacuumwas maintained in the vaporizer equal to about 2% to 3 inches ofmercury. The,oil was fed at the rate of about 100 cubic centimeters perminute. The water was fed at the rate of about 10 cubic centimeters perminute. The gas leaving the ap paratus showed about the followinganalysis:

Per cent by volume CO2 2. 9 O2 2. 9 Olefine hydrocarbons 2. 5 CO 4. 8

A total volume of 25.5 liters of oil was fed and 19.6 liters of oilyproduct insoluble in water was Per cent Aldehyde fatty acids 31Aldehydes above 200 C 20 Alcohols. other proouot'ofi"fi.;;ofioi (bydifference) 49 An Engler distillation of the product gave the following:

Per cent Upto100C I .5 100 to 150 c 2. 5 150 to 200 C 11.0 200 to 250 C21. 5 250 to 300 C 38 5 300 to 340 C 23. Above 340 C 3.0

In this preferred multiple layer type, by proper regulation of the airadmitted to the various chambers and of the temperature in thesuccessive reaction zones, I am able to carry the oxidation to the pointof maximum yield of aldehyde fatty acids and of low molecular weighthydrocarbons. In this system, I may employ, for the first or the firstand second catalytic layers, a material which gives predominantoxidation to one stage, for example, the aldehyde stage. This effect isquite marked with the intermediate oxides of uranium and their compoundsas a catalyst. For the remaining layers, it is desirable to usecatalytic material which has the particular characteristic of carryingthe oxidation to the acid stage, such as molybdenum trioxide or theintermediate oxides of molybdenum. It will be understood that I regulatethetemperature in the reaction zone or at each catalytic layer accordingto the catalyst used and the degree of oxidation which has previouslybeen reached before passing the succeeding layers.

In this-case again, steam will aid in vaporizing heavier petroleumfractions and also in keeping the catalyst freed from deposits whichwould tend to coat it and retard the flow. While the steam will retardthe action in one layer, this is more than compensated for by the totaldepth of catalyst, either in one layer or the series of layers shown.

In this case, the temperature may also be controlled within the desiredlimits, by regulating the amount of air fed, and if desired, by cooling,regulating the vaporizing and heating burners, etc., as well as byadding the diluent.

I may also, in this multiple screen form, vaporize the oil and pass itthrough the first layer (in this case preferably a relatively deep one)without adding air before contact. This will give thermal decompositionand increase the olefin content; and then by adding air between thefirst and second layers and beyond, if desired, in the proper amount,the partial oxidation will proceed in the succeeding layers more easilyon account of the increase in unsaturated bonds in the hydrocarbonchains. Similarly, the thermal treatment with a catalytic layer may becarried out and the product condensed and then re-vaporized, air addedand passed through a layer for partial oxidation.

In Figure 3, I show a simple form of apparatus with a deep catalyticlayer IO 2 being the vaporizing and air-mixing chamber and I the outletto the condenser and suction device, if this is used. I have used asmall apparatus of this I;

kind with a diameter of catalytic layer of 38 centimeters and a depth of28 centimeters. A thermometer is placed at the entrance to the catalyticlayer.

Withthis apparatus, I employed two conde and six scrubbers, each of thelatter being filled with gas oil.

In the first run, I used gas oil having at C. a specific gravity of.841. The oil feed was 100 cubic centimeters per hour, and the air ratetwo liters per minute. The total oil fed was 380 cubic centimeters, andthe temperature of the reaction zone about 400 C.; 245 cubic centimetersof product were obtained from the condensers and absorbers.

Analysis of the product gave 17.4% of a motor spirit distilling under200 C.; 19.7% of aldehyde fatty acids; 14% of aldehydes, and 13.3% ofalcohols and unconverted hydrocarbons; these percentages being figuredback on the oil fed.

In the second experiment with the same apparatus, and conditions thesame, except that steam was added to the system equal to of waterrelative to the oil fed, I obtained 11.2%

of a. motor spirit distillate distilling under 200 C.; 24.9% of aldehydefatty acids; 27.1% of aldehydes and 22.1% of alcohols and hydrocarbons;these percentages being figured on the oil treated.

In a further experiment, similar to that of the first experiment, exceptthat the temperature was reduced to 380 C., the total recovery ofproduct increased to 86%, with a corresponding lowering in the gas loss.This shows, in accordance with many other experiments, that the reactionis so sensitive that slight changes in the factors make great changes inthe proportion of the various products of yield in a given run.

In carrying out my process, it may be varied in accordance with thematerial treated, and the conditions in several ways. By varying thealiphatic raw material employed, I have found that in most cases and formany purposes the shorter the range of the cut or distillate, thenarrower is the range of the desired products. Thus, for certain gradesof products, I may employ gas nsers I ill oil or fuel oil distillates;distill these to obtain two fractions, and treat these fractions forcertain purposes. a

Again, I may take topped California crude oil, give it one distillationand use the upper fraction for my process. Crude oils and theirdistillates vary in several ways, some having a paraffin base and somean asphaltlc base. The crude contains saturated straight chain orbranched chain aliphatic hydrocarbons. It may also contain unsaturatedstraight chain or branched chain hy drocarbons. such as those of theolefin type and those of the acetylene type. It may also containaromatic hydrocarbons with side chains, the latter being saturated orunsaturated, and naphthenes. My process which is a low temperature,

vapor phase air oxidation, relates to attacking the chain hydrocarbons,as distinguished from the aromatic hydrocarbons of the benzene ringtype. and it operates more easily on thealiphatic hydrocarbons of theunsaturated type. Because of the highly unsaturated condition of aconsiderable portion of the hydrocarbons of the cheaper petroleums, Ifind that the formation of oxidation products by my process takes placeeasier than with the saturated aliphatic hydrocarbons. For that reason,I prefer in some cases to prepare material for my improved process bythe cracking" distillation of crude oil from the Western States, or ofMexican crude oil, or of htavy distillates thereof; followed by applyingmy partial combustion process to either the entire distilled oil, or toseparate fractions thereof. Olefin kerosenes and heavier fractions highin olefins can be made by cracking distillation of gas oil and otherheavy fractions at atmosphcric pressure. Then by submitting the same tomy process, a good percentage of light oil, such as motor spirit, and atthe same time a large proportion of intermediate combustion products canbe obtained, such as aldehyde fatty acids, aldehydes, alcohols, waxes,etc.

For the same reasons as noted above, I can successfully treat shale oilby my process. This oil has too high a percentage of olefins to beeasily Worked up into ordinary petroleum products.

I may, for example, take topped California crude oil or a heavydistillate thereof, such as fuel oil, and distill it in a high verticalstill. After distilling in the ordinary manner to take off the kerosenefraction, I-lower the heat and slow down the distillation so that thevapor rising into the upper part of the still will fall back and besubjected to repeated thermal treatments causing cracking. Thisoperation will convert the heavy fraction into oil lying in the heavierkerosene "ill range and in the gas oil range. It will also produce aconsiderable proportion of olefins, usually from 20 to 25%. I preferablycontinue this slow cracking distillation, either until nothing is leftbut coke, which must be dug out, or until the residue has just enoughfluidity to tap out of the still. If this cracking distillation iscarried on to where the residue is coked, the operation is stopped whenthe distilling operation shows no condensate forming from the vapors.The products then formed are merely gases. I then take this distillatewhich consists of heavy olefin kerosome and olefin gas oil (sinceolefins are present to a large extent), and subject them to the partialcombustion process. The olefin end of this distillategreatly aids inproducing partial com-.

are thefbprresponding saturated hydrocarbons. The atmospheric pressurecracking still formerly used to. increase the kerosene fraction may beused for this purpose.

I may distill the oil (preferably by a cracking distillation) andpassthe oil vapor from the still directly into my apparatus in any desiredform thereof. In this case the vapor may be passed through a preliminaryheated layer where further thermal decomposition may take place, andthen be mixed with air and passed on through the catalytic screen orscreens and partially converted into intermediate oxidation products. Orafter the thermal decomposition, the vapors may be condensed, the lightoil removed, and the remainder passed through my partial combustionprocess.

The total depth of catalyst has an influence on the products,particularly as regards the amount of light oil produced and thepercentage of the partial combustion product which will polymerize.

The particular catalyst employed is also of importance, as somecatalysts are more active than others. Thus, for producing mainlyalcohols and ,aldehydes, I preferably employ a catalyst of loweractivity. For single layer work, in producing aldehyde fatty acids, Ipreferably employ cataiyti material of greater activity.

The temperature of the reaction zone, the percentages of air suppliedrelative to the hydrocarbon feed, the velocity of the current of mixedvapor and air, the use of steam or other diluent, and other factors alsoare useful in affording elasticity to the process and varying the amountand character of the product. By such variations, I can make a largerproportion of alcohols and aldehydes, or a larger proportion of aldehydeacids; and I can vary the quality of these products and the percentagesof light oil obtained.

As regards the catalyst employed, I prefer the complex oxides orcompounds of metals having a varying valence. All parts of the complexmay consist of oxides of the same metal or of different metals. Forexample, an excellent catalyst in this connection consists of theso-called blue oxides of molybdenum, which contain molybdenylmolybdenate (MOO2MOO3) and molybdenyl molybdenite, and areprobably allchemical compounds of two or more oxides of molybdenum representingdifferent states of oxidation. These complexes may be regarded as salts;that is, compounds of one or more basic with one or more acid oxides.

Other complexes of value for such catalysts are chromic chromate,CizOaCl'Oz, tungsten tungstate, WOzWOs, the manganese complexes, thevanadium complexes, etc.

The basic and acid parts of these complexes may be formed from oxides ofdifferent metals, in which case each metal or group of metals usedshould possess varying valence.

Examples of this class are:

Uranyl uranate (UrO2) 2UrzOs These metals whose complexes I'prefer toemploy as the acid part of the catalyst, since I have found them to beof high activity in this field, are the metals of high melting pointelectronegative low-atomic-volume metals having an atomic weight above40. These metals appear on the Lothar-Meyer diagram of the periodicseries becombined. Under the above conditions, which reach anequilibrium of temperature in the catalytic zone, the temperature willbe below that of self-sustained complete combustion-that is, below theigniting point where complete combustion will be continuouslymaintained. At the same time, this condition may be properly termed acondition of self-sustained combustion in the sense that the partialoxidation occurs continuously below the igniting point or belowself-sustained complete combustion of a large part of the mixture.

The steam performs a cooling effect, as does the radiation from thecatalytic zone. The percentage of air fed also aids in this controlling,in each case there being a balance maintained between the heat of theincoming gases, the heat generated by the partial oxidation reactions,the heat carried away by the exit gas, the radiation and conduction ofheat, etc. This may also be added, as above shown, by artificialcooling. The radiating effect from the catalytic zone is, of course,greater in the case of smaller diameter catalytic chambers than withlarger chambers, and the other cooling conditions are maintained toaccord with the amount of radiation, conduction, exothermic reaction,etc. This heat balance is maintained whether or not the raw materialused is a liquid fraction which is vaporized by heat,

there being a regulation of the amount of heat supplied for vaporizing,etc., or whether the raw material is a. gas at normal temperatures andpressures. As above shown, with the larger diameter catalytic chamberthe excess heat may be carried away by the addition of diluents, by theproducts of oxidation themselves, by varying the ratio of air containingfree oxygen in relation to the hydrocarbon, and by artificial cooling,if desired. In all these cases the balance between the heating andcooling effects are maintained so that, as above shown, the temperatureis maintained at the desired point above recited. In a true sense thetemperature is that of self-sustained combustion, that is,self-sustaining partial oxidation which proceeds continuously below acontinuously maintained ignition point at which continuous completecombustion proceeds.

Since the oxidation is considered to be by stage partial oxidation, theamount of air at any preliminary stage will of course be relativelysmall as the air is supplied at intervals between screens, preferably inabout the amounts above referred to.

The process may be employed either with the thin layer catalyst or thedeep layer catalyst, or the multiple screen process with successive airadmission. It may also be employed with double run or rerun material inwhich is repeated.

Many changes may be made in the raw material used, the catalystemployed, the number of stages of oxidation, etc., without departingfrom my invention.

I claim:

1. In the process of catalytic oxidation of petroleum hydrocarbons, thestep which comprises passing the reaction mixture of petroleum vapor andair over a catalytic mass maintained at a black heat just below a lowred heat under conditions of self-sustaining combustion.

2. In the process of making partial combustion products, stepsconsisting of mixing finely divided petroleum oil with air in measuredamount, passing the mixture in contact with a catalyst and maintainingthe catalyst at a temperature below a red heat under conditions ofself-sustaining combustion.

3. The process of making partial combustion products, which comprisesvaporizing petroleum oil, mixing oxygen and diluent with these vapors,and passing the mixture through a catalyst maintained at a temperaturebelow a red heat under conditions of self-sustaining combustion.

4. In the process of making partial combustion products, the steps whichconsist of passing a mixture of petroleum oil vapor and 'air through acatalyst at a temperature below a red heat under conditions ofself-sustained combustion.

5. In the process of making partial combustion products, the stepsconsisting of passing a mixture of heated petroleum oil vapor, air and adiluent through a reaction zone at a temperature below a red heat underconditions of self -sustained combustion.

6. In the catalytic oxidation of petroleum oils the step which comprisespassing a mixture of petroleum oil vapor and air over a compositecatalyst containing two active oxdizing agents maintained at a blackheat approaching red heat under conditions of self-sustained combustion.

7. In the process of producing valuable oxidation products, the stepwhich comprises subjecting hydrocarbons containing naphthenes tooxidation under conditions of self-sustaining combustion.

8. A process as set forth in claim '7, in which the oxidation step iscarried out at a black heat just below a red heat.

9. A process as set forth in claim 7 in which the oxidation step iscarried out at a temperature below a red heat.

10. The process which comprises passing cracked oil and air over acatalyzer at such a rate of speed and at such a temperature that freeoxygen is present in substantial amount in the exit gases wherebyoxygen-containing organic products are obtained.

11. The process which comprises passing cracked petroleum oil and airover a catalyzer at such a rate of speed and at such a temperature thatfree oxygen is present in substantial amount the oxidizing step in theexit gases whereby oxygen-containing organic products are obtained.

JOSEPH I-HDY JAMES.

